JPS583503B2 - Thai Netsame Yozai Varnish Noseizou Hohou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a heat-resistant, solvent-free varnish that is odorless and has a long pot life.

The gist of the present invention relates to the production of a novel unsaturated polyester-based varnish composition having the above-mentioned characteristics, which is based on an unsaturated oligoester having an allyl group introduced at the end of the molecule.

Unsaturated polyesters are conventionally used as solvent-free varnishes that cure by radical reaction and have been used as general paints and varnishes for electrical insulation treatment.

Most of the polyester varnishes are prepared by dissolving maleate-based and/or flamato-based prepolymers in sunalene monomer.

Although such conventional unsaturated polyester varnishes have the advantages of low viscosity and fast curing, they suffer from problems such as bad odor and physiological adverse effects on the human body due to volatilization of the styrene monomer, and furthermore, the varnish's It also has the disadvantage of short usage time.

Moreover, the cured product itself contains a large amount of polystyrene crosslinked chains derived from styrene monomer, and has poor heat resistance stability.

As a means of improving the above-mentioned drawbacks of conventional unsaturated polyester varnishes, it is possible to use a vinyl monomer (snarene) with a high boiling point and a heptanomer crosslinked chain with excellent thermal stability. .

Allyl compounds such as diallyl phthalate and triallyl trimellitate are examples of versatile monomers that meet these requirements.

However, as is well known, the polymerization process of allyl compounds has specificities such as large degenerative chain transfer and easy formation of closed ring structures, and the monomer viscosity is lower than that of sunalene monomers. The compound is approximately twice as high as the -C number, and in order to reflect the dilution effect of the livarnish system, a large amount of this compound must be added, which is more pronounced than the specificity of the polymerization reaction.

Therefore, in conventional unsaturated polyester varnishes,
When an allyl compound is used instead of the snalene monomer,
The resulting cured product contains a large number of closed ring moieties and molecular ends that do not participate in the crosslinking chain, and a quantified version of the allyl compound itself, and the resulting network structure is heterogeneous and has various properties. If anything, they will be at a disadvantage.

The present inventors conducted intensive research to develop a new unsaturated polyester varnish that eliminates all of the above-mentioned drawbacks, and as a result, the molecular structure of the unsaturated polyester varnish was changed to an unsaturated prepolymer with an allyl group at the molecular end/allylic monomer. By doing so, it is possible to obtain a new solvent-free varnish that has good curing reactivity and exhibits excellent properties of the cured product, and has favorable workability such as the varnish system being odorless and having an extremely long pot life. We have reached the following knowledge.

There are many unclear points as to why the molecular structure of the unsaturated polyester varnish of the present invention improves the polymerization and curing reactivity of allyl groups, but one explanation is that, for example, diallylphthalate prepolymers have excellent curing properties. An example of giving something can be given.

That is, the diallyl phthalate prepolymer is a precursor polymer of diallyl phthalate monomer, and an allyl group is present at the pendant 11 at the end of the molecule.

In the case of such a molecular structure, the crosslinking curing rate of the allyl group increases, which suggests a correlation with the molecular design of the unsaturated polyester varnish of the present invention.

The gist of the present invention is the general formula (wherein R1 represents a glycol residue and R2 represents a dibasic acid residue.

(n is an integer of 1 to 10) An oligoester compound with an unterminated hydroxyl group (A)
1 mol and the general formula (where R2 represents a dibasic acid residue.

) Diallyl ester (B) 2. 2-10
This is a method for producing a solvent-free varnish composition obtained by deallylating alcohol in moles in the presence of a small amount of an alcoholysis reaction catalyst and a polymerization inhibitor.

The feature of the present invention is that the diallyl compound (B) is blended in an amount in excess of the amount of hydroxyl groups in the oligoester compound having a hydroxyl group at the end of the molecule. This means that it can be provided as a service.

The compounds used in the present invention have the general formula HO-R, -OH
Glycols represented by (a) such as ethylene glycol, diethylene glycol, triethylene glycol,
One or several mixtures of propylene glycol, dipropylene glycol, neopentyl glycol, hydrogenated bisphenol A, trimethylene glycol, etc., and a dibasic acid represented by the general formula HOOC-R2-COOH, or an anhydride or lower version of the acid. Alkyl esters such as phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid and their anhydrides, isophthalic acid, terephthalic acid and their methyl and ethyl esters, succinic acid, maleic acid and their anhydrides, adipic acid, fumaric acid, etc. It can be obtained by carrying out a conventional esterification reaction with one or a mixture of acids and the like under conditions in which glycol component (a) is added in excess.

At this time, the degree of polymerization n in the general formula (A) may be determined by adjusting the blending of the glycol component (a).

It is best to determine n from the range of 1 to 10; if n is larger than 10, the final varnish will have a high viscosity, which will cause inconvenience in actual operations such as coating, impregnation, and casting. This is because it becomes like this.

The resulting molecularly terminated hydroxyl group oligoester compound (
A) is then reacted (alcolyzed) with diallyl compound starch B).

Preferably used diallyl compounds include, for example, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl succinic acid, diallyl maleic acid, and the like.

The solvent-free varnish composition of the present invention has good properties when it is obtained by blending 2.2 to 10 moles of the diallyl compound (B) to 1 mole of the molecularly terminated hydroxyl group oligoester component (A). show.

If the amount of component (B) is less than 2.2 moles, the hydroxyl groups of the component may not be completely converted into allyl esters, which is not preferable.

On the other hand, if the amount of component (B) is more than 10 moles, the amount of monomer (i.e., remaining diallyl compound) in the final face composition will be too large, and the cured product may become brittle or There is a tendency for impact resistance to decrease.

Therefore, the blending of component (B) with component (A) is determined based on the above-mentioned range and the molecular structure of component (A) (for example, the type of molecular chain element (a) or (b) and the degree of polymerization n). It is better to choose.

The solvent-free varnish composition of the present invention is prepared by adding a small amount of an alcoholysis catalyst and a polymerization inhibitor to the above-mentioned oligoester compound (A) with a terminal hydroxyl group and a diallyl compound (B) to carry out an alcoholysis reaction (deallyl alcoholization). obtained by.

As alcoholysis catalysts, those used in normal esterification reactions such as baraxylene sulfonic acid, paratoluene sulfonic acid, dominium acetate, lead acetate, sulfuric acid, and tetrabunal titanate can be used as they are, and the amount added can be 0.
It may be 1 to 5% by weight.

In addition, common polymerization inhibitors such as hydroquinone, quinhydrone, hydroquinone monomethyl ether, sulfur flower, and copper powder can be used, and the amount added is 0.01 to 3% by weight.
That's fine.

The alicolysis reaction can be carried out at a temperature of 150-240°C.

The thus produced solvent-free varnish of the present invention contains one or more of polymerization initiating catalysts such as penzoyl peroxide, dicumyl peroxide, t-bunal perpenzoate menal enal ketone peroxide, and chthonic hydroperoxide. A mixture of seeds is usually added in an amount of 0.5 to 5% by weight.
An excellent cured product can be obtained by heating to 30 to 180°C.

Although the solvent-free varnish produced according to the present invention can be used as is, it may be used for purposes such as slightly modifying the properties of the cured product, such as imparting flexibility or changing the curing reactivity of the varnish. It is permissible to add small amounts of other vinyl monomers for this purpose.

Such monomers include, for example, skillene, vinyltoluene, alcohol esters of (meth)acrylic acid (such as methyl, ethyl, proyl, butyl esters, etc.), glycol diesters of (meth)acrylic acid (such as enalene glycol di( meth)acrylate, propylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, bis(meth)acryloxyalkyl isophthalate, bis(meth)acryloalkyl phthalate, bis(meth)acrylate ) acryloxyalkyl terephthalate, bis(meth)acryloxyalkyl hexahydrophthalate, bis(meth)acryloxyalkyl tetrahydrophthalate, etc.).

The details of the present invention will be further explained below with reference to Examples.

Example 1 2.2 moles (137.9) of ethylene glycol, 1.0 mole (194.9) of dimethyl isophthalate, and 0.25% by weight of paraxylene sulfonic acid were mixed with a stirring bar, a thermometer, a fractionating tube, and nitrogen. The mixture is charged into a 2-liter four-hole flask equipped with a gas blowing tube and esterified at 120 to 150°C, and 98% of the theoretical amount of methanol is distilled off to obtain bishydroxyethyl isophthalate.

Next, 31 moles (762 g) of diallyl isophthalate, 0.3% by weight of paraxylene sulfonic acid, and 0.1% by weight of hydroquinone were added to carry out an alcoholysis reaction at 180 to 210°C, and the theoretical amount of allyl alcohol of 98 or more was distilled off. I let it happen.

The varnish thus obtained consists of an unsaturated polyester having an allyl group at the end of the molecule and a diallylisophthalate monomer (monomer content 30% by weight).
It was odorless and had a value of 20 poise at 0°C.

2 parts by weight of dicumyl peroxide as a polymerization catalyst was added to 100 parts by weight of the varnish, and the resulting mixture was poured into an aluminum petri dish and cured by heating at 150°C for 8 hours.
A cured product having an extremely good appearance and a pencil hardness of 7H was obtained.

The cured product had a heating reduction rate of 1.7% after being heated at 200° C. for 100 hours.

The varnish containing a polymerization catalyst was heated at 60° C. for 10 days, but the rate of increase in viscosity was about 10%.

Example 2 22 moles (167 g) of propylene glycol and 1 mole (152 g) of tetrahydrophthalic anhydride were esterified in the same manner as in Example 1, and more than 95% of the theoretical amount of reaction product water was distilled off to produce bishydroxypropyl. Tetrahydrophthalate is obtained.

Next, 3.1 moles (762 g) of diallyl phthalate, 0.3 mole of paraxylene sulfonic acid, and 0.3 mole of hydroquinone.
25% by weight of each was added and an alcoholysis reaction was carried out in the same manner as in Example 1 to obtain a solvent-free varnish consisting of an unsaturated polyester having an allyl group at the end of the molecule and a diallyl phthalate monomer.

The varnish was odorless and had a value of 18 poise at 30°C.

When a mixture of 100 parts by weight of this varnish and 2 parts by weight of dicumyl peroxide as a polymerization catalyst was heated at 150°C for 8 hours, a cured product having an extremely good appearance and a pencil hardness of 6H was obtained.

The cured product had a heating reduction rate of 240% after being heated at 200° C. for 100 hours.

Further, when the polymerization catalyst-added varnish was left for 10 days under heating at 60° C., the rate of increase in viscosity was about 8%.

Comparative example 1 Propylene glycol 1.1 mol, phthalic anhydride 0.5
Polypropylene phthalate maleate having an acid value of 13 was synthesized from mol and 0.5 mol of maleic anhydride by a conventional method, 30 parts by weight of styrene monomer was added to 70 parts by weight of the unsaturated prepolymer, and the mixture was heated to 11 parts by weight at 30°C. I used poise varnish.

The varnish naturally has a strong styrene odor.

A mixture obtained by adding 1 part by weight of penzoyl peroxide as a polymerization catalyst to 100 parts by weight of the varnish was heated at 80°C for 3 hours and then at 130°C for 5 hours, and the heating reduction rate and pot life of the cured product were measured in the same manner as in the examples. When evaluated,
The heating reduction rate was 18.7%, and the pot dry gelatinized in 5 hours.

As mentioned above, the solvent-free varnish produced by the present invention is odorless, has a long pot life, and the cured product obtained also has excellent properties. It is clear that this is of great significance.

Claims (1)

[Scope of Claims] 1 An oligoester compound with an unterminated hydroxyl group represented by the general formula (where R2 is a glycol residue, R2 is a dibasic acid residue, and n is an integer from 1 to 10) A
) 1 mol and a diallyl ester (B) represented by the general formula (wherein, R2 represents a residue of a dibasic acid) 2. 2-10
A method for producing a heat-resistant solvent-free varnish obtained by deallylating alcohol in the presence of a small amount of an alcoholysis reaction catalyst and a polymerization inhibitor.